Pneumatic tires, particularly those used on vehicles in industrial, farming, and construction projects, are susceptible to punctures which require that the vehicle be taken out of service for so long as is required to repair the tire. These vehicle tires are generally subjected to hostile terrain and severe loading conditions which greatly increase the liklihood of puncturing. Furthermore, since these vehicles are generally driven at slow operating speeds the usual advantages offered by pneumatic tires by way of improved vehicle handling and operating efficiency are not available.
In recent years, fluid elastomers such as polyurethane have been developed for injecting into pneumatic tires to create a solid puncture proof tire for wheels used in applications as described above. Improved elastomers, including plural component fluids have been developed which, when hardened, provide a solid material having a low specific gravity and a great many micron-sized hollow cavities. Such a material is described in U.S. Pat. No. 3,866,651, issued Feb. 18, 1975. Another such material is described in U.S. Pat. No. 3,866,652, issued Feb. 18, 1975. These materials, and other similar materials which may be injected into a pneumatic tire in a fluid state and which solidify upon curing, may be used with the present invention, which comprises a method and apparatus for injecting such fluids.